61A-8 |
Structures and physicochemical properties of six wild rice starches |
L. WANG1, Y. J. Wang1, and R. Porter2. (1) Department of Food Science, University of Arkansas, 2650 N. Young Ave., Fayetteville, AR 72704, (2) North Central Research and Outreach Center, University of Minnesota, Grand Rapids, MN 55744 Starches from six wild rice cultivars grown in Minnesota in 2000 were studied for their chemical structures and physicochemical properties and compared with those of a long-grain rice starch. Wild rice starches exhibited similar properties, morphological appearance, and X-ray diffraction patterns as the rice starch. The wild rice starches had a significantly higher swelling power and water solubility index but lower beta-amylolysis limit compared with the rice starch. The onset gelatinization temperature of rice and wild rice starch were 72.1°ãC and 58.9-61.0°ãC, respectively, and the enthalpy 14.1 and 10.5-11.0 J/g, respectively. The peak viscosity of wild rice, ranging from 328 to 401 units, was much higher than that of the rice starch (240 units). The amylopectin of the six wild rice starches showed similar branch-chain length distributions. Wild rice starches consisted of more short branch-chains with DP 6-12 than did the rice starch, but fewer long branch-chains with DP 37-63.
Session 61A, Carbohydrate
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